1944 NBC broadcast of the Ben Hecht & Kurt Weill Holocaust "dramatic pageant" We Will Never Die. Live from the Hollywood Bowl.
The U.S. Holocaust Memorial Museum has a couple web pages about this production:
"Kurt Weill and We Will Never Die" http://www.ushmm.org/wlc/en/article.php?ModuleId=10007047
"We Will Never Die: Shattering the Silence Surrounding the Holocaust" http://www.ushmm.org/wlc/en/article.php?ModuleId=10007036
The program had a cast of 1,000 and among them: Edward G. Robinson, Edward Arnold, Joan Leslie, John Garfield, and Paul Henreid.
FYI: this is the same program that the Old Time Radio Researchers Group distributed as "Hollywood Bowl Holocaust Special" in their The Singles and Doubles Collection (here on Archive.org) with a date of the 4th of July 1944.
Any error or typo is mine. :)